Alpha Scattering Experiment

• What did the ancient Greeks believe about atoms?

  They believed that everything is made of tiny, indivisible spheres called atoms
• What significant discovery was made in 1897 regarding atoms?

  Atoms contain tiny negative particles called electrons
• How did the discovery of electrons change the perception of atomic structure?

  It indicated that atoms have an internal structure rather than being indivisible spheres
• What is the name of the model that scientists proposed after discovering electrons?

  The Plum Pudding model
• What does the Plum Pudding model depict?

  An atom as a ball of positive charge with negative electrons embedded in it
• What experiment did scientists conduct to test the Plum Pudding model?

  The alpha scattering experiment
• Why is the alpha scattering experiment considered important?

  It radically changed the way scientists think about atoms
• What material did scientists use for the alpha scattering experiment?

  Gold foil
• Why did scientists choose gold for the alpha scattering experiment?

  Because it can be hammered into very thin foil just a few atoms thick
• What are the particles fired at the gold foil in the alpha scattering experiment called?

  Alpha particles
• What is a key fact about alpha particles?

  They have a positive charge
• What did scientists conclude from the observation that most alpha particles passed straight through the gold foil?

  Atoms are mainly empty space
• What did the deflection of some alpha particles indicate?

  The center of the atom must have a positive charge
• What does the bouncing back of some alpha particles suggest about the atom's center?

  The center of an atom must contain a great deal of mass
• What term do we use to refer to the central part of an atom?

  The nucleus
• How did the results of the alpha scattering experiment affect the Plum Pudding model?

  It led to the replacement of the Plum Pudding model with the nuclear model
• What is the nuclear model of atomic structure?

  • Most of the atom is empty space
  • The center contains a tiny positive nucleus
  • The nucleus contains most of the mass of the atom
  • Negative electrons are located around the edge of the atom
• What will be covered in the next video?

  A more detailed look at the nuclear model of atomic structure
• Where can students find questions on this topic?

  In the vision workbook linked in the video